1. Field of the Invention
The present invention relates a method for modifying (grafting) surfaces of a substrate and sidewalls of high-aspect holes with reduced graphene oxide (rGO) by a wet process.
2. Related Prior Art
U.S. Pat. No. 5,389,270A disclosed a composition beneficial to uniformly dispose graphite on sidewall surfaces of non-conductive through holes as a conducting layer for electroplating process. The composition consists essentially of an aqueous dispersing medium, graphite having a micrometer particle size, a dispersing agent for dispersing the graphite particles, a binding agent for binding the graphite particles to the sidewall surfaces of the non-conductive through holes, and a surfactant for wetting the through hole.
Before electroplating, a fixing solution is preferably applied to remove redundant graphite particles in the through holes and to smooth the graphite coating on the sidewall of the through holes. The fixing solution may either be water or a dilute acid.
Patent WO 2013/096273 disclosed a graphene layer as a barrier layer between a first metal layer and a second metal layer. The graphene layer is formed on a template layer of Cu or Ni by chemical vapor deposition and then transferred to a surface of the second metal layer.
U.S. Pat. Nos. 8,884,310B2 and 9,343,533 disclosed a method for directly forming graphene on semiconductor substrates. This method comprises steps of: (a) depositing a layer comprising a carbon-rich polymer on the front surface of the semiconductor substrate; (b) forming a metal film on the carbon-rich polymer layer by sputtering, evaporation, electroplating or metal foil bonding; (c) heating the semiconductor substrate (500° C.-1000° C.) to drive carbon to diffuse into the subsequently applied metal film; (d) precipitating carbon atoms to form a layer of graphene on the surface of the semiconductor substrate by rapidly cooling the semiconductor substrate; and (e) etching the metal film away to render graphene on silica-on-silicon substrate.
U.S. Pat. No. 9,105,696 disclosed a method for coating a layer of reduced graphene oxide (rGO) on the surface of substrate holes. This method includes: (Step 1) hydrophilic treatment of the surface of the substrate; (Step 2) forming a self-assembly silane layer on the surface of the substrate and the holes; (Step 3) grafting a polymer layer on the self-assembly silane layer; (Step 4) immersing the treated substrate from Step 3 in an alkaline GO solution to graft a GO layer on the polymer layer; (Step 5) immersing the treated substrate from Step 4 in a solution of metal ion to intercalate the metal ions into the GO layer; and (Step 6) immersing the treated substrate from Step 5 in a solution of reductant to reduce the metal ion into metal atom, and the GO layer into a reduced graphene oxide (rGO) layer to form a metal atom/rGO composite layer on the substrate surface and the hole surface.